COURSE: Aeroelasticity

Transcription

1 SESSION WEEK COURSE: Aeroelasticity DEGREE: Aerospace Engineering YEAR: 4th TERM: 1st La asignatura tiene 29 sesiones que se distribuyen a lo largo de 14 semanas. Los laboratorios pueden situarse en cualquiera de ellas. Semanalmente el alumnos tendrá dos sesiones, excepto en un caso que serán tres DESCRIPTION WEEKLY PLANNING Aeroelasticity & Dynamic Loads. Getting Started. - Aeroelasticity as a multidisciplinary task - Normal modes at a glance - Stability problems vs. Response problems - Basic flutter mechanisms. CS D Aeroelasticity: fixing concepts with some analytical 2D solutions - The ¾ span aerofoil. Pitch and plunge modes. - Revisiting steady aerodynamics. The standard atmosphere. - Introduction to 2D unsteady aerodynamics. Wagner, Küssner, Theodorsen. - Solution of the 2D aeroelastic equation. - Sensitivity to cg. GROUPS (mark ) LECTU RES SEMIN ARS SPECI AL ROOM FOR SESSIO N (Comp uter class room, audiovisual class room) Indic ate YES/ NO If the sessi on need s 2 teac hers WEEKLY PROGRAMMING FOR STUDENT DESCRIPTION CLASS HOURS HOME WORK HOURS (Max. 7h week) 1,6 1 Página 1 de 5

2 D & 3D Static aeroelasticity: divergence and control reversal - Static aeroelasticity of a 2D rigid aerofoil. - Static aeroelasticity of a fixed wing - Divergence. Effect of sweep angle on divergence speed. - Control effectiveness. Effect of wing flexibility on control effectiveness. PROPOSAL OF HOMEWORK 1 3D Aeroelasticity: The structural model & the normal modes - Revisiting 1 d.o.f system. - Multiple d.o.f. systems - The Finite Element Method (FEM) for structural analysis. - From stick models to full FEM models. The stiffness matrix. - Mass models. The mass matrix. - Condensation. - Structural Normal modes. Frequencies and mode shapes. HOMEWORK 1 DELIVERY The experimental modal analysis and the GVT. Dynamic model validation. - Ground Vibration Test (GVT) description. - Introduction to Digital Signal Processing (DSP). The Fast Fourier Transform (FFT). - Experimental Modal Analysis. - Comparison between test and simulations. MAC. - Updating FEM model to match GVT results. 3D Aeroelasticity: unsteady aerodynamics, origins (Wagner, Küssner, Theodorsen). Rodden and the Doublet Lattice Method (DLM) - Continuing with 2D unsteady aerodynamics. - The Finite Element Method (FEM) for aerodynamic analysis. - Rodden and the Doublet lattice Method - Aerodynamic corrections to match wind tunnel or flight tests. Partial Exam 1: Aeroelastic Modelling The flutter equation and its solution (natural aircraft) - Derivation of flutter equation from Lagrange equations. - Complex matrix eigenvalues & eigenvector solution. - Evolution of modal frequency and modal damping with flight speed. - The V-g plot unveiled - Physical description of classical lifting surface flutter mechanisms - Airworthiness regulations CS (and the evolution from FAR and JAR ) Work on HM01 1, Flutter speed sensitivities. Control surface massbalance. Aeroservoelasticity (coupling Página 2 de 5

3 with Flight Control System laws) - Sensitivity analyses: mass configuration, Mach number, control surface aerodynamic hinge moment, etc. - Physical description of classical control surface flutter mechanisms. - Sensitivity to control surface mass balance. - Covering uncertainties & addressing failure cases (structural single failures, damage tolerance, water ingress, composite delaminations...) - Revisiting aircraft controls. Introduction to aircraft flight control system laws. - Aeroservoelasticity. - Physical description of most common aeroservoelastic couplings. Flight Flutter Test. Aeroelastic model validation. Wrap up of aeroelastic stability problems. - Flight Flutter Test (FVT) description. - Aircraft response to control surface sweeps and pulses. - Revisiting Digital Signal Processing (DSP). Noise treatment. Averaging. Windowing. Aliasing. Leakage,... - Experimental Modal Analysis applied to Flight Test. - Comparison between flight test and simulations. Scatter. - Wrap up of aeroelastic stability problems. Partial Exam 2: Aeroelastic Stability The concept of loads. Monitoring stations. Checkstress loads and fatigue loads. Dynamic loads and why they are different form static loads. Structural response to transient excitation. - What is fast and what is slow - Direct response vs. Modal response - Frequency domain response - Time domain response Ground dynamic loads: dynamic landing & Taxi - Relevance of the dynamic landing and taxi scenarios. Insight into the airworthiness regulations. - Dynamic Landing Loads equations. Spin-up and spring back. - Taxi loads equations. Coupling landing gear and complete aircraft. - Solution. Relevant parameters. - Complete loads loop process. - Validation: Landing Gear (L/G) Drop Test. Hard landings. (1-cos) taxi tests. Unpaved surfaces taxi tests. - Where the structure is sized by dynamic landing. By Taxi, EBH curves for operation in unpaved surfaces. PROPOSAL OF HOMEWORK 2 Página 3 de 5

4 Dynamic flight loads: discrete tuned gust (DTG) - The atmospheric turbulence. Discrete and continuous models - Relevance of the discrete tuned gust (DTG) analyses. Insight into the airworthiness regulations. - DTG equation. The spiral gust column. Solution. Relevant parameters. - Complete DTG loads loop process. - Validation: FVT. Description of where the structure is sized by DTG. Round the clock and multiaxis. Dynamic flight loads: continuous turbulence (CT) - Relevance of the Continuous Turbulence analyses. Insight into the airworthiness regulations. The von Karman spectrum. - CT equation. Frequency domain solution using Power Spectral Density (PSD). - The contribution of the rigid body modes. Solution. Relevant parameters. - Complete CT loads loop process. - Validation: FVT. Description of where the structure is sized by CT. HOMEWORK 2 DELIVERY Dynamic flight loads: buffet. Wrap up of aeroelastic response problems. - Relevance of the Buffet loads. - Wing buffet. HTP buffet. Fin buffet. L/G doors buffet. - Test to measure buffet response. - PSD technique to compute buffet loads. Work on HW02 Work on HW02 15 Partial Exam 3: Aeroelastic Response (Dynamic Loads) 1,6 Subtotal Total 1 (Hours of class plus student homework hours between weeks 1-14) Tutorials, handing in, etc Assessment 3 1 Subtotal Total 2 (Hours of class plus student homework hours between weeks 15-18) 4 TOTAL (Total 1 + Total 2. Maximum 90 hours) 90 Página 4 de 5

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